Objective To investigate the way of inducing dendritic cells from precursor in human cord blood and its role in antitumor immunity.Methods Cord blood was collected under sterile condition and the cord blood mononuclear cells were separated by centrifugal in density gradient.CBMCs were cultured with GM-CSF+IL-4+TNF-?and cell phenotype was analyzed with CD1a、CD83 antibody by using indirect immunofluorescence assays.The effects of DCs pulsed with tumoral antigens on cytotoxic T lymphocytes(CTLs) inducement and growth inhibition of YTMLC cells were assayed.Results Our results indicated that DCs precursors in human cord blood can be induced to differentiate in the medium containing GM-CSF、IL-4 and TNF-?.The cells with typical morphological properties of DCs were observed at the 7th day.At that time,(20.8?1.62)%CD1a+ cells were obtained.After incubation with tumor cytolysis antigen,the DCs can activate the CTLs to become tumor specialized CTLs,which had shown significantly inhibition on growth of YTMLC tumor cell line.Conclusion The precursors in human cord blood can be induced to functional DCs which activate T lymphocyte to become tumor specialized CTLs.